BREAKING: Mass shooting reported at California bar

Multiple people have reportedly been injured following a violent incident in Thousand Oaks, California -about 40 miles west of Los Angeles. The Ventura County Sheriff's Deputies responded to reports at Borderline Bar and Grill, around 11:30 pm local time.

While the extent of the victims' injuries has not yet been released, some publications have been estimating that dozens were injured. At least one person was seen being taken out on a stretcher, before being placed in an ambulance.

Local reports have claimed that a gunman shot a security guard at the front of the bar, before entering the building. The suspect, described as bearded and wearing a hat and glasses, threw smoke grenades inside, before he shot and injured a female cashier.

Witnesses told ABC 7 that he was armed with a handgun, and that at least a dozen shots were fired before patrons attempted to escape, using chairs to smash windows.

One police officer was among at least six people that were injured, according to the Sheriff's Office. Captain Garo Kuredjian said that it was "still a very active scene," and that "there are several injured inside the bar and grill including one deputy sheriff".

"Dozens of personnel behind me that are trying to get to the bottom of what happened and to neutralise the threat, if the threat is still active."

Both SWAT and bomb squad teams have been called to the area to ensure the safety for those nearby, while emergency services have started treating those at the scene. Ventura County Fire Department issued a statement, in which they said:

“The police showed up, three of them went to the door," one witness told CBS. "Currently, there was one officer down as they were breaching the front entrance."

According to the bar's official website, they were holding a 'College Country' night at the time of the shooting.

Update:

Officials have now confirmed that the suspect in the attack is now dead, and that out of the 200 or so patrons at the bar that night there were at twelve people killed. The shooter was found dead in the bar by authorities, who are currently looking for a motive.

"We just dropped to the ground, we heard a lot of screaming," one witness told local news station KTLA. "My friend is the DJ so she cut off the music, we just heard a lot of mayhem."

Ventura County Sheriff's office spokesman Eric Buschow said:

"When deputies arrived they heard shots being fired, it was an active shooter situation.

"They entered the location and I can tell you there are multiple fatalities, multiple injuries, among the victims is one of our sheriff's deputies that responded in that initial call, as well as the shooter."

The officer killed was Sgt. Ron Helus, who was the first on the scene. He was shot multiple times and rushed to the hospital, where he later succumbed to his injuries.

This is a developing story and will updated as more information becomes clear.